Anastomosis is a procedure where two separate tubular or hollow organs are surgically grafted together to form an intercommunication between them. Vascular anastomosis involves creating an anastomosis between blood vessels to create or restore blood flow. The vascular anastomosis procedure is routinely performed during the treatment of a variety of conditions, including coronary artery disease, diseases of the great and peripheral vessels, organ transplantation, traumatic injury and other vascular abnormalities. When a patient suffers from coronary artery disease (CAD), an occlusion or stenosis in a coronary artery restricts blood flow to the heart muscle. In order to treat CAD, the area where the occlusion occurs is bypassed to reroute blood flow by grafting a vessel in the form of a harvested artery or vein, or a prosthesis. When the vessel is grafted to bypass the blocked coronary artery, the occlusion is circumvented and adequate blood flow is restored to the heart muscle. This treatment is known as a coronary artery bypass graft procedure (CABG).
When a conventional CABG is performed, a large incision is typically made in the chest of a patient and the sternum is sawed apart and separated in order to allow access to the heart of the patient. Moreover, the patient is connected to a heart-lung machine which circulates and oxygenates the blood of the patient. After the heart-lung machine is connected to the patient, the patient's heart is stopped in order to facilitate the vascular anastomosis. Sawing the sternum and stopping the heart are both traumatic events, and require substantial recovery time, particularly in older patients. Further, the patient may experience a variety of physiologic abnormalities after disconnection from the heart-lung machine.
In order to minimize the trauma to the patient induced by the CABG, less invasive techniques have been used. These less invasive techniques include making a series of small incisions in the patient's chest. Once the incisions are made, surgery is performed through the incisions with the aid of visualizing scopes. This procedure is often referred to as closed chest or port-access CABG surgery. The less invasive techniques may be performed on a beating heart without use of the heart-lung machine in order minimize trauma to the patient.
In both conventional and less invasive CABG techniques, a surgeon typically sutures one end of the graft vessel to the coronary artery beyond the narrowed area and the other end of the graft vessel to a blood supplying artery, such as the aorta, in order to bypass the occlusion. Prior to suturing the graft vessel to the coronary arteries, called target vessels, an incision is made in the target vessel to allow suturing of the graft vessel to the target vessel. Typically, the surgeon cuts the incision in the target vessel to an appropriate length depending on a size of the graft vessel in order to suture the graft vessel to the target vessel. However, a great amount of skill and time is required in making the incision, aligning the graft vessel to the incision and performing the anastomosis due to the small size and configuration of the target blood vessel. Closed chest bypass graft surgical procedures using sutured anastomosis techniques are disclosed in U.S. Pat. Nos. 5,452,733 and 5,735,290.
Sutureless techniques for performing anastomosis have also been proposed. Such techniques are disclosed in U.S. Pat. Nos. 3,254,650; 3,774,615; 4,350,160; 4,352,358; 4,368,736; 4,523,614; 4,553,542; 4,593,693; 4,607,637; 4,624,255; 4,624,257; 4,657,019; 4,747,407; 4,907,591; 4,917,087; 4,917,090; 4,917,091; 5,119,983; 5,234,447; 5,336,233; 5,366,462; 5,456,714; 5,571,167; 5,669,918; 5,676,670; 5,695,504; 5,702,412; 5,707,380; 5,725,544; 5,797,920; 5,817,113; and 5,904,697. However, these existing sutureless techniques for performing anastomoses have certain shortcomings that render them less practical or desirable for use in performing coronary bypass surgery in the closed chest.
Consequently, a need still exists for an automated system for performing bypass graft surgery which allows a surgeon to make a precise anastomosis between each end of a graft vessel and a corresponding target vessel.